x = torch.tensor([-2.7920,-2.2356,-1.8285,-1.7755, -1.7408, -1.0992,
                     -0.9828,-0.9527,-0.2743,-0.2406, -0.0918, 0.1785,
                      0.2922, 0.3702, 0.3957, 0.4205,   0.5041, 0.5499,
                      0.6154, 0.9958, 1.2607, 1.2784,   1.4159, 1.9559])
x1 = torch.tensor(x** 1, dtype=torch.float32).reshape(-1, 1)
x2 = torch.tensor(x** 2, dtype=torch.float32).reshape(-1, 1)
x_input = torch.cat([x1, x2], dim=1)  # (24,2)
y_target = 0.5*x**1 + 3.*x**2 + 0.4*x**3   # (24,1)
y_true = y_target.reshape(-1, 1)
